The present study analyzed for the first time the behaviour of CD4+FOXP3+ T
regulatory cells (Tregs) in the peripheral blood of human subjects undergoing
a psychological stressor. It has previously been shown that acute
psychological stress alerts the adaptive immune response causing an increase
in antigen-experienced effector T cells in the peripheral blood. Tregs play a
central role in maintaining self-tolerance and controlling autoimmune
responses. 31 healthy young males underwent a brief laboratory stressor and,
in a crossover design, served as their own unstressed controls. Effects of
acute stress on CD4+FOXP3+ T regulatory cells and other T cell subpopulations
have been quantified using flow cytometry. In addition, the expression of
Treg-related effector molecules has been analyzed in the subjects’ peripheral
CD4+ T cells. Acute psychological stress caused a decrease in CD4+FOXP3+ Tregs
and in CD4+ T cells expressing Treg-related effector molecules “Cytotoxic
T-lymphocyte associated protein-4” (CTLA-4) and “Latency Associated Peptide”
(LAP). The previous observation of a stress-induced decrease in CD45RA+CCR7+
“naïve” and CD45RA-CCR7+ “central memory” T cells has been confirmed while
CD45RA-CCR7- “effector memory” and CD45RA+CCR7- “terminally differentiated”
effector T cells remained stable or increased. In conclusion, inhibiting
components of the adaptive immune response, like Tregs, are down-regulated
during an acute stress-induced activation of the adaptive immune response. In
situations of repeated stress exposition, this scenario might result in an
exacerbation of inflammatory conditions such as autoimmune diseases.